Broadband communication access, on which our society and economy is growing increasingly dependent, is becoming more readily available to users on board mobile platforms such as aircraft, buses, ships, trains and automobiles. Typically, mobile platform communications systems that provide such access utilize electromagnetic communication signals, also generally referred to in the art as radio frequency (RF) signals, to communicate with a remote, typically ground based, system. To increase available bandwidth, some known mobile platform communication systems have implemented optical, i.e. laser, communication systems in addition to the electromagnetic systems.
Generally, known communication systems for mobile platforms that provide both optical/laser and electromagnetic modes of communication require separate optical and electromagnetic apertures. Thus, such systems generally include at least one optical terminal and at least one separate electromagnetic antenna mounted on the mobile platform. However, separate optical and electromagnetic apertures/antennas add additional equipment costs, add significant weight and occupy valuable space which may not be available on a given mobile platform.
Commonly, combined communication systems utilize satellite dishes, phased arrays and telescopes to provide for the communication of both optical and electromagnetic signals. For example, at least one known system includes a small planar electronically scanned electromagnetic phased array antenna and at least one separate optical phased array (OPA) terminal. However, the phased array antenna and the OPA must be implemented separately and care must be taken to implement both systems such that each performs to expectation at the expense of increased physical space consumption. Additionally, when separate optical and electromagnetic systems, specifically the optical terminals and electromagnetic antennas, are mounted on the mobile platform in close proximity, alignment and calibration become difficult to optimize. Therefore, set-up of such systems can be very time consuming and performance often inhibited.
Therefore, it would be desirable to add additional communications bandwidth by adding optical communications to a mobile platform communications system while minimizing the footprint of the exterior communications equipment, e.g. antenna and related electronics, on the mobile platform.